Daniel 4:16

Let his heart be changed from man's— It can only be hence collected, that the king's mind was so changed, that he now appeared to himself no longer as a man, but as an animal; and therefore, of his own accord, lived among wild beasts, neglectful of human food and culture. Nothing is read concerning the change of his form; he therefore crept upon his hands and feet like other animals; in this alone unlike a man, that his hair and nails increased like those of an eagle: see Daniel 4:33. By seven times are meant seven years. Times is used in the same sense in the Revelation. Scaliger thinks that this madness of Nebuchadnezzar is obscurely hinted at in a fragment of Abydenus, produced by Eusebius; wherein, having represented the king, from the Chaldean writers, to have fallen into an exstasy, and to have foretold the destruction of that empire by the Medes and Persians, the author adds, that immediately after uttering this prophesy he disappeared; which Scaliger expounds by the king's being driven from his regal state, and the society of men. See Houbigant and Calmet.